1. Field of the Invention
The present invention relates to a connection structure of a coaxial harness. In particular, the present invention relates to a connection structure of a coaxial harness such that, when a plurality of coaxial harnesses, each comprising a plurality of micro coaxial cables, are connected to a substrate, a planar dimension of its connection part may be downsized.
2. Description of the Related Art
In recent years, electronic devices represented by portable phones have been rapidly downsized, become lesser in weight, and become multifunctional. According to such a trend in technology, it has become indispensable to downsize the wiring materials and terminal connectors used in electronic devices.
According to information equipment such as a cellular phone, a displaying part, comprising a liquid crystal panel and the like, and a main body part of the equipment are connected with a hinge part. Between the displaying part and the main body part of the equipment, it is necessary to provide a wiring structure which may be twisted.
As a wiring structure serving this purpose, a flexible printed circuit (hereinafter referred to as FPC) and a coaxial harness which is obtained by binding a plurality of coaxial cables and the like is known, compared to conventional structures.
Further, as the information equipment becomes smaller and smaller in size and becomes thinner and thinner, conservation of space and the reduction of radius are being carried out with respect to these wiring structures as well. Thus, a further conservation of space is being demanded.
A known connection structure for this coaxial harness is shown in FIGS. 5 to 7. According to this connection structure for this coaxial harness, each grand bar 21, 22, connected respectively to coaxial harnesses 1A, 1B stacked in a plurality of layers (two layers in the diagrammed example), is connected respectively to a plurality of ground bar connection terminal 17 (17A, 17B) provided on a substrate 15. FIG. 5 is a planar view of the substrate 15 used in this conventional connection structure of the coaxial harness. FIG. 6 is a cross sectional view of the conventional connection structure of the coaxial harness. FIG. 7 is a planar view of the conventional connection structure of the coaxial harness.
At a lower most portion of the substrate 15 used in the conventional connection structure of the coaxial harness, a first grand bar connection terminal 17A is provided as shown in FIG. 5. At an upper portion of this first grand bar connection terminal 17A, a first center conductor connection terminal group 19 is provided such that a plurality of center conductor connection terminal 18A are aligned in one line. Furthermore, a second ground bar connection terminal 17B is provided on the substrate 15, at an upper portion of this first center conductor connection terminal group 19. At an upper portion of this second ground bar connection terminal 17B, a second center conductor connection terminal group 20 is provided such that a plurality of center conductor connection terminal 18B are aligned in one line.
According to this conventional connection structure of the coaxial harness, an electric connection is made between the first ground bar 21 and the first ground bar connection terminal 17A. The first ground bar 21 is provided on the coaxial harness 1A in the first layer. The first ground bar connection terminal 17A is provided on the substrate 15. At the same time, an electric connection is made respectively between each center conductor 3A of the coaxial harness 1A in the first layer and the first center conductor connection terminal group 19. In addition, an electric connection is made between the second ground bar 22 and the second ground bar connection terminal 17B. The second ground bar 22 is provided on the coaxial harness 1B in the second layer. The second ground bar connection terminal 17B is provided on the substrate 15. At the same time, an electric connection is made respectively between each center conductor 3B of the coaxial harness 1B in the second layer and the second center conductor connection terminal group 20.
However, according to this structure, as the number of layers in the coaxial harness increases, there is also an increase in the proportion of the planar dimension of the connection part between the substrate and the coaxial harness on the substrate. As a result, it becomes difficult to reduce the size of the connection structure of this coaxial harness.
An example of a prior art technology aimed to reduce the size of the connection part of the connection structure of the coaxial harness is suggested and disclosed in Japanese Unexamined Patent Application, First Publication No. 2007-287541 (hereinafter referred to as Patent Document 1).
This Patent Document 1 discloses a cable harness. The cable harness comprises a connection terminal connected to each end terminal part of a plurality of coaxial cables. According to this cable harness, the connection terminal is structured by an FPC. This FPC comprises a bending part so that the FPC may be used while being bent. The connection part between the FPC and the coaxial cable is placed in both sides of the bending part of the FPC. The direction in which the FPC is bent at the bending part is a direction perpendicular to a longitudinal direction of the coaxial cable connected to the connection part.
However, according to the conventional technology disclosed in Patent Document 1, a special processing of this FPC is necessary in order to fold up the FPC. Furthermore, an extra procedure, such as wrapping a tape around the FPC, becomes necessary so that the FPC does not open up after being folded up. As a result, there is a problem in that the manufacturing cost of the cable harness disclosed in Patent Document 1 becomes high.
The present invention is made in light of these problems. An object of the present invention is to provide a connection structure such that, when a plurality of coaxial harnesses, comprising a plurality of coaxial cables, are connected to a substrate, a planar dimension of the connection part may be reduced and an increase in manufacturing costs is prevented. As a result of reducing the planar dimension of the connection part, a connection may be made with a greater number of coaxial cables.